【题目】 The real reason why prices ____ , and still are, too high is complex, and no short discussion can satisfactorily explain this problem.
A. were B. will be
C. have been D. had been
在线课程【答案】A
【解析】试题分析：句意：过去和现在价格一直居高不下的真正原因很复杂，简短的讨论解释这一问题无法让人满意。根据题干中“and still are”的提示可知过去价格也居高不下，故用一般过去时，表示过去的状态。故选A项。